linux-kernel - Re: [PATCH v2 4/4] spi: spi-davinci: Add support for SPI_CS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 13 Sep 2018 15:44:43 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     David Lechner <david@...hnology.com>
Cc:     linux-spi <linux-spi@...r.kernel.org>, linux-iio@...r.kernel.org,
        Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald <pmeerw@...erw.net>,
        Mark Brown <broonie@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 4/4] spi: spi-davinci: Add support for SPI_CS_WORD

Hi David,

On Thu, Sep 13, 2018 at 2:40 AM David Lechner <david@...hnology.com> wrote:
> This adds support for the SPI_CS_WORD flag to the TI DaVinci SPI
> driver. This mode can be used as long as we are using the hardware
> chip select and not a GPIO chip select.
>
> Signed-off-by: David Lechner <david@...hnology.com>
> ---
>  drivers/spi/spi-davinci.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
> index d502cf504deb..8f7dcbc53c57 100644
> --- a/drivers/spi/spi-davinci.c
> +++ b/drivers/spi/spi-davinci.c
> @@ -230,7 +230,8 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value)
>                                 !(spi->mode & SPI_CS_HIGH));
>         } else {
>                 if (value == BITBANG_CS_ACTIVE) {
> -                       spidat1 |= SPIDAT1_CSHOLD_MASK;
> +                       if (!(spi->mode & SPI_CS_WORD))
> +                               spidat1 |= SPIDAT1_CSHOLD_MASK;
>                         spidat1 &= ~(0x1 << chip_sel);
>                 }
>         }
> @@ -440,8 +441,12 @@ static int davinci_spi_setup(struct spi_device *spi)
>                         return retval;
>                 }
>
> -               if (internal_cs)
> +               if (internal_cs) {
>                         set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
> +               } else if (spi->mode & SPI_CS_WORD) {
> +                       dev_err(&spi->dev, "SPI_CS_WORD can't be use with GPIO CS\n");
> +                       return -EINVAL;

Does the SPI core fall back to splitting the transfer in this case?

> +               }

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds